My Salt water report card.

[saanich2018]

Good description of EMI, but mineralization does not cause RF EMI as it is just a passive constituent of whatever type of ground you are swinging the coil over. Passive meaning that it is not a transmitter of radio frequency EMI.

EMI and ground noise (caused by mineralization/black sand) are two entirely different things and require two different mitigations.

EMI is caused by external ACTIVE sources of electromagnetic energy transmission in the radio frequency spectrum such as power lines, wi fi transmitters, flourescent lights, cell towers, cell phones, walkie talkies, transformers, electric fences, etc. The noise cancel feature on Equinox and other detectors is designed to counter this issue by selecting a quiet channel on which the detector can "hear" the target signal with minimum interference. Sometimes the EMI is severe and/or broad spectrum enough (e.g., wireless dog fences) that noise cancel is not sufficient, such that you have to lower detector sensitivity to reduce chatter, but that also limits target depth. Since multifrequency detectors are tuned to listen over a broad range of frequencies, they tend to be more susceptible to EMI in general. For Equinox, another option is to switch it to single frequency. You lose the multifrequency benefits, but at least you may find a frequency you can detect at without turning sensitivity down too low. The lower frequencies (5 to 10 khz) tend to be more susceptible to EMI.

Ground noise feedback/chatter manifested by random, constant iron tones and negative VDI numbers is caused by the detector responding to mineralization/black sand which is comprised of ferrous oxide (essentially rust) in the ground. Since these particles are ferromagnetic, they readily couple to the receive coil and throw off the induction balance between the transmit and recieve coils (the principle behind which VLF IB defectors such as Equinox use to detect and discriminate different targets). This effect is cancelled out by properly ground balancing the detector at the start of your detecting session or using tracking ground balance if the ground effects are constantly changing due to changes in mineralization. Another thing that can increase ground chatter is sweep speed and recovery speed. Slower sweep speeds and slower recovery speeds tend to increase ground noise, so lowering recovery speed too far (in an attempt to "increase" depth performance) can increase ground noise effects and actuslly lower target detection ability.

On salt beaches or alkalai soils, the conductivity effects of salt also play a similar but different role in causing ground chatter due to upsetting the ground effect cancellation and multi frequency machines actually have an advantage over single frequency machines in this regard, because they can process, recognize, and cancel the instabilities by salt effects at different frequencies. This is the reason multifrequency can run more stable than single frequency machines on wet salt sand or in salt water.

If you have black sand AND salt, Equinox tries to mitigate that situation in Beach 2 mode by automatically dialing back transmit power (not sensitivity) when it senses black sand mineralization. Using tracking GB in this situation can also help in the surf when wave action is churning up the sand and causing constant changes in salt and mineralization levels.

Bottom Line:

EMI - external ElectroMagnetic Interference due to radio transmitter sources. Mitigate by doing a noise cancel, lower sensitivity, or try single frequency, if necessary.

Ground noise - Ground balance (and use tracking if ground mineralization requires constant rebalancing), keep recovery speed near the defaults, and use the multifrequency beach modes on salt sand (Beach 1 for wet sand, Beach 2 for surf and with black sand).

HTH

Corretc - I do stand corrected. Thanks

 

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[midalake]

I'd say something was wrong with your detector. If it were an inherent problem with the Equinox, all of us would be have "your" problem. I have well over 600 hours on mine now and don't have the issues you seem to have.

Maybe you do not have my conditions? After a long lay off, I was back on the Nox yesterday. I tried to run a program cjc gave me, then switched back to my program. I can tell you the Nox has many issues in and around moving salt water. Yesterday I had numerous finds that I could not hear until the wave wash was off the beach.

Also the EMI interference from cell phones is silly. I was working on a target yesterday and had 4 people watching me with cell phones. The chatter was crazy and could not recover the target until these people moved along.

I can hear cells phones coming at me from 20' to 15' away.


Also for some reason the numbers on the nox would just not lock in, jumping around all over. Tried several different things to get the machine to lock better but could not get it done yesterday.


Dave

 

[cudamark]

Maybe you do not have my conditions? After a long lay off, I was back on the Nox yesterday. I tried to run a program cjc gave me, then switched back to my program. I can tell you the Nox has many issues in and around moving salt water. Yesterday I had numerous finds that I could not hear until the wave wash was off the beach.

Also the EMI interference from cell phones is silly. I was working on a target yesterday and had 4 people watching me with cell phones. The chatter was crazy and could not recover the target until these people moved along.

I can hear cells phones coming at me from 20' to 15' away.


Also for some reason the numbers on the nox would just not lock in, jumping around all over. Tried several different things to get the machine to lock better but could not get it done yesterday.


Dave

Like I said, I believe it's your detector that is the problem. I hunt in an out of the salt water with a live cell phone in my pocket without an issue. Now if I get around a cell tower or WiFi, then yeah, EMI can be a pain. Also, heavy black sand can make it erratic to where you have to reduce sensitivity and slow your sweep speed. In the water, I haven't found that to be an issue. It's in the wet or dry sand that I notice it.

 

[JOe L]

Maybe you do not have my conditions? After a long lay off, I was back on the Nox yesterday. I tried to run a program cjc gave me, then switched back to my program. I can tell you the Nox has many issues in and around moving salt water. Yesterday I had numerous finds that I could not hear until the wave wash was off the beach.

Also the EMI interference from cell phones is silly. I was working on a target yesterday and had 4 people watching me with cell phones. The chatter was crazy and could not recover the target until these people moved along.

I can hear cells phones coming at me from 20' to 15' away.


Also for some reason the numbers on the nox would just not lock in, jumping around all over. Tried several different things to get the machine to lock better but could not get it done yesterday.


Dave

As with the case, I would be on the phone with Minelab. Your not happy, talk to them.

 

[midalake]

]Like I said, I believe it's your detector that is the problem.[/B] I hunt in an out of the salt water with a live cell phone in my pocket without an issue. Now if I get around a cell tower or WiFi, then yeah, EMI can be a pain. Also, heavy black sand can make it erratic to where you have to reduce sensitivity and slow your sweep speed. In the water, I haven't found that to be an issue. It's in the wet or dry sand that I notice it.

Well yesterday was the day had been waiting for in a long time. I have a friend who has a Nox 800 and is very accomplished on land with it. In fact if most of you were to see his colonial silver finds with the Nox you would pass out.

YESTERDAY, started working with my machine for the first hour and a half, same issues in moving salt water as normal. Unhooked my machine and plugged his into my phones and the next hour and a half was exactly like my machine. Zero difference in depth, sounds, target ID issues, recovery, lost targets in moving salt water. I also did testing with different recovery speeds and IB, as compared to sensitivity. Worked tracking GB as well as fixed 0 GB. Standing by all of my original reporting and just stating that there are issues with the Nox in moving salt water.


Dave

 

[cudamark]

Looks like you need to use it for colonial silver and get something else for your salt water site.